As large expanses of semi-arid grasslands west of the Mississippi River were converted into crop producing areas in the 20th Century, native perennial plants, such as grasses, shrubs and flowers, were removed. A large portion of these grasslands have for many years been planted to crop plants, in particular various varieties of winter wheat. As historical fluctuations in the value of farm commodities have made the economies of growing dry land grain crops, as opposed to grazing cattle, somewhat uncertain, many farmers have chosen to take such land out of production and return it to grasslands. The problem encountered in this conversion is that not only the desirable grasses and shrubs naturally reseed these formerly tilled areas. Typically, a large number of undesirable plants exemplified by Russian and Canadian Thistle and Morning Glory, invade the disturbed area and effectively compete with the more desirable native or introduced rangeland plants, such as Crested Wheat Grass, Blue Bunch Grass, Side Oats Grama, Silver Sage Brush, Winterfat, Penstemons, Yarrows, etc.
Various attempts have been made to reseed such areas in the more desirable native grasses and shrubs, but because the areas involved (in many cases thousands of acres) are so great, a ready supply of an adequate seed source has been difficult if not impossible to assure. Methods of harvesting such native seed sources have been relatively inefficient, resulting in extremely high prices for such seeds, thereby making reseeding of such areas financially impracticable. For instance, the prices currently being charged for various common rangeland seeds are: Crested Wheat Grass, $3.50/pound; Great Basin Wild Rye, $7.00/pound; Western Wheat Grass, $5.50/pound. Depending upon the variety, it can take anywhere from 22 to 50 pounds per acre of grass seeds and from 30 to 40 pounds per acre of shrub seeds to adequately replant tilled areas. Such costs are prohibitive over large areas.
Given the agricultural surpluses occurring in the production of corn, wheat and barley in the United States and Canada in the decade of the 1980's, the U.S. Government has instituted a Conservation Reserve Program whereby farmers are paid to remove certain cropland from production and return it to its native state. These are lands which are highly erodable and which were placed in production when profit margins were high enough to make such marginally productive land profitable. The incentives for so doing are sufficient to induce relatively large numbers of farmers to enter the program (approximately 10 million acres in 1986 were accepted).
Therefore, it is an object of the present invention to provide an apparatus which efficiently harvests native seeds from grasses, shrubs and flowers so that they may be used to reseed formerly tilled areas. Such apparatus is more effective than prior seed harvesting apparatus, and therefore can provide such native seeds at a lower cost, thereby increasing the incentive to replant to native vegetation.
Seed harvesting devices for attachment to tractors and/or combines are well known in the art. For example, U.S. Pat. No. 4,373,322, Beisel, discloses a seed harvester which combines a rotating brush member with an elongate hollow housing, wherein when the device is moved through a seed-bearing grass crop, the brush "flails" the seeds from the plant and propels them rearwardly into the housing. Air movement into the device is such that a portion of the debris removed by the brush exits the device through a forward-facing exit. Seeds removed from the plants are deposited in a rearward portion of the housing by centrifugal force. Likewise, U.S. Pat. No. 2,693,072, Belzer et al., discloses a grass seed harvester which is preferably pulled behind a tractor through a grass crop. The device comprises a seed-harvesting brush carried within a housing and an impeller mounted within a duct interconnecting the housing and a seed collector. The impeller and its housing are located at the rearward end of a suction-chamber through which the seeds pass when traveling from the brush to the seed collector. A similar device is disclosed in U.S. Pat. No. 1,297,349, Herr, in which a rotating brush directs seeds into a fan housing. Suction into a drum where the seeds and hulls are separated. The mixed product is then discharged onto a vibrating screen, with the seeds dropping through the screen and the hulls being discharged over the screen.
U.S. Pat. No. 2,345,969, Halley, et al., discloses a seed harvester in which a rotating brush strips seeds from plants and deposits them on an elevator canvas. Deflectors are provided, which apparently remove seeds entrained in the bristles of the brush. Lastly, U.S. Pat. No. 1,587,349, Otis, et al., discloses a seed harvester in which a clam shell-type hood is provided with a rotating brush therein. The hood is constructed such that seed bearing plants are forced within the hood where upon the brush removes the seeds therefrom and deposits them in receptacles within the hood.
Brush fires or range fires in the Western U. S. often burn large expanses of native vegetation. As is the case with former crop land, natural reseeding of burned-over areas many times results in a predominance of unwanted or undesirable plant species. In order to assure such burned over areas are returned to the most desirable condition (i.e., for cattle and wild life grazing), it is advantageous that such areas be mechanically reseeded if sufficient economical supplies of such seeds were available.
Lastly, there is a need for an effective seed harvesting device for harvesting seeds from certain commercial seed crops. For instance, while there are devices currently marketed which will harvest seeds from alfalfa plants, the nature of the seed habit, i.e., a plurality of seeds is arranged in a helically shaped "curl", requires that a multi-step procedure be utilized in order to acquire seeds suitable for planting. Additionally, certain commercially valuable seed sources, such as wild rice, wheat, barley and other grains, flowers and selected seed or vegetable crops could advantageously be harvested by use of the present invention.